Radio frequency identification (RFID) tags are inexpensive wireless microchips used to identify physical objects. RFID tags are present in a variety of physical objects, including passports, drivers' licenses, shipping cases, clothing, payment cards, etc. A major driver of the deployment of RFD systems is to prevent and detect counterfeiting, or the introduction of fake goods into a supply chain. By affixing RFID tags directly to goods or the cases in which they are transported, supply chain partners can automatically track goods in transit, facilitating the detection of counterfeit goods. RFID tags typically emit unique identifiers. A supply chain partner can in principle confirm an object's authenticity by checking its serial number against a shipping manifest or with a directory service spanning supply chain partners. Electronic Product Code (EPC) Information Services (EPCIS) is one example of such a directory service. Counterfeit detection is of vital importance to many industries in which counterfeit goods cause large profit losses. In some industries, such as the pharmaceutical industry, counterfeit goods may also lead to patient deaths.